Such a transfer system for carrying out the assembling of parts, while circulating a pallet with a work placed thereon along a transfer line forming a closed loop is conventionally known (see Japanese Patent Publication No. 4-57555). In the above known transfer system, a pallet-shaped carriage on which a work can be placed is circulated on rails placed along a quadrilateral transfer line. In this case, the carriage is allowed to travel by connecting and disconnecting an endless chain, circulatively driven along the rails by a drive source, to or from the carriage, or the carriage is allowed to travel pitch by pitch by bringing the carriage into and out of engagement with a rack which is reciprocally driven through a predetermined distance along the rails by a drive source, and during this time, the assembling of parts to the work placed on the carriage is carried out.
However, since it is necessary to supply parts to be assembled to a work from the outside, to the carriage in succession, the above known system suffers from a problem that, when a plurality of transfer lines are additionally provided in the system, it is difficult to secure a space for smoothly supplying the parts to these transfer lines and to enhance the working efficiency.